SEARCH · Engineering Papers

Results for “containers”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59

All sources NASA NTRS DOE OSTI

NASA NTRS1977

Three-dimensional elastic stress and displacement analysis of finite geometry solids containing cracks

The line method of analysis is applied to the Navier-Cauchy equations of elastic equilibrium to calculate the displacement fields in finite geometry bars containing central, surface, and double-edge cracks under extensionally applied uniform loading. The application of this method to these equations leads to coupled sets of simultaneous ordinary differential equations whose solutions are obtained along sets of lines in a discretized region. Normal stresses and the stress intensity factor variation along the crack periphery are calculated using the obtained displacement field. The reported results demonstrate the usefulness of this method in calculating stress intensity factors for commonly encountered crack geometries in finite solids.

Kring, J.↗

NASA NTRS1977

Aldehyde-containing urea-absorbing polysaccharides

A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.

Mueller, W. A.↗

NASA NTRS1976

Development testing of a self-contained heat rejection module

This paper discusses the thermal vacuum testing of a Self-Contained Heat Rejection Module (SHRM) currently being developed for use with Shuttle payloads and future spacecraft. Two weeks of testing were conducted in the NASA Johnson Space Center Space Environment Simulator Laboratory in October and November of 1975. The testing included demonstration of deployable spacecraft radiators with fluid swivels, variable return temperatures, and a dual-mode pumped fluid radiator/vapor compression refrigeration system. In addition, an evaluation was made of a contact heat exchanger used as the intercooler. The test articles and systems are described and the test planning and objectives discussed. A summary of the significant results of the testing and conclusions drawn from the testing are presented.

Fleming, M. L.↗

NASA NTRS1976

Ductile fracture of cylindrical vessels containing a large flaw

The fracture process in pressurized cylindrical vessels containing a relatively large flaw is considered. The flaw is assumed to be a part-through or through meridional crack. The flaw geometry, the yield behavior of the material, and the internal pressure are assumed to be such that in the neighborhood of the flaw the cylinder wall undergoes large-scale plastic deformations. Thus, the problem falls outside the range of applicability of conventional brittle fracture theories. To study the problem, plasticity considerations are introduced into the shell theory through the assumptions of fully-yielded net ligaments using a plastic strip model. Then a ductile fracture criterion is developed which is based on the concept of net ligament plastic instability. A limited verification is attempted by comparing the theoretical predictions with some existing experimental results.

Erdogan, F.↗

NASA NTRS1977

Concepts for the development of light-weight composite structures for rotor burst containment

Based on published results on rotor burst containment with single materials, and on body armor using composite materials, a set of hypotheses is established as to what variables might control the design of a weight-efficient protective device. Based on modern concepts for the design and analysis of small optimum seeking experiments, a particular experiment for evaluating the hypotheses and materials was designed. The design and methods for the analysis of results are described.

Holms, A. G.↗

NASA NTRS1977

TOMCAT - A code for numerical generation of boundary-fitted curvilinear coordinate systems on fields containing any number of arbitrary two-dimensional bodies

A method for automatic generation of boundary-fitted curvilinear coordinate systems, where the transformed coordinates are solutions of an elliptic differential system in the physical plane, and where the coordinate lines are coincident with all boundaries of a general multiply-connected, two-dimensional region containing any number of arbitrarily shaped bodies, and is described along with a suitable computer code for implementing the method. Any partial differential system can be solved on the boundary-fitted coordinate system by appropriate transformations. The transformed equations are approximated by finite differences and solved numerically in the transformed plane. All computations, whether for generating coordinate system or then solving the transformed equations, can be done on a rectangular field with square mesh with no interpolation required on the boundaries. The physical boundaries may even be time-dependent.

Thompson, J. F.↗

NASA NTRS1977

Three-dimensional elastic stress and displacement analysis of finite geometry solids containing cracks

Kring, J.↗

NASA NTRS1979

Fire-retardant covering for small containers

Flexible intumescent sheets of exceptionally uniform thickness may be used to protect containers and other small objects less than 25.4 cm in diameter from fire hazards.

Riccitiello, S. R.↗

NASA NTRS1977

Development of fiber shields for engine containment

Tests were conducted in translational launchers and spin pits to generate empirical data used in the design of a Kevlar shield for containing engine burst debris. Methods are given for modeling the relationship of fragment characteristics to shielding requirements. The change in relative importance of shield mounting provisions as fragment energy is increased is discussed.

Bristow, R. J.↗

NASA NTRS1977

Concepts for the development of light-weight composite structures for rotor burst containment

Published results on rotor burst containment with single materials, and on body armor using composite materials were used to establish a set of hypotheses about what variables might control the design of a weight-efficient protective device. Based on modern concepts for the design and analysis of small optimum seeking experiments, a particular experiment for evaluating the hypotheses and materials was designed. The design and methods for the analysis of results are described. The consequence of such hypotheses is that the device should consist of as many as four concentric rings, each to consist of a material uniquely chosen for its position in the penetration sequence.

Holms, A. G.↗

NASA NTRS1977

Analysis of delamination in unidirectional and crossplied fiber composites containing surface cracks

A two-dimensional hybrid stress finite element analysis is described which was used to study the local stress field around delamination cracks in composite materials. The analysis employs a crack tip singularity element which is embedded in a matrix interlayer between plies of the laminate. Results are given for a unidirectional graphite/epoxy laminate containing a delamination emanating from a surface crack through the outside ply. The results illustrate several aspects of delamination cracks: (1) the localization of the singular stress domain within the interlayer; (2) the local concentration of stress in the ply adjacent to the crack; (3) the nature of the transverse normal and interlaminar shear stress distributions; and (4) the relative magnitudes of K sub 1 and K sub 2 associated with the delamination. A simple example of the use of the analysis in predicting delamination crack growth is demonstrated for a glass/epoxy laminate. The comparisons with experimental data show good agreement.

Wang, S. S.↗

NASA NTRS1978

Development and evaluation of die and container materials

Commercial high purity ultrafine Si3N4, Al2O3, and SiO2 powders were vacuum dried and stored under nitrogen in sealed containers. Extensive analysis of the chemical, physical, and morphological characteristics of these powders was performed. The interaction of molten silicon with fused quartz was examined in a Knudsen cell using a mass spectrometer. The solubility of oxygen at the melting point of silicon was calculated to be 1.78 times 10 to the 18th power atoms/cu cm, and the activity coefficients of oxygen and silicon monoxide, the major vapor species, were calculated to be 4.83 times 10 to the minus 24th power and 0.0000701, respectively.

Wills, R. R.↗

NASA NTRS1978

Stress intensity factors in bonded half planes containing inclined cracks and subjected to antiplane shear loading

The antiplane shear problem for two bonded dissimilar half planes containing a semi-infinite crack or two arbitrarily located collinear cracks was considered. For the semi-infinite crack the problem was solved for a concentrated wedge load and the stress intensity factor and the angular distribution of stresses were calculated. For finite cracks the problem was reduced to a pair of integral equations. Numerical results were obtained for cracks fully imbedded in a homogeneous medium, one crack tip touching the interface, and a crack crossing the interface for various crack angles.

Bassani, J. L.↗

NASA NTRS1978

Preliminary investigation of crack arrest in composite laminates containing buffer strips

The mechanical properties of some hybrid buffer strip laminates and the crack arrest potential of laminates containing buffer strips were determined. The hybrid laminates consisted of graphite with either S-glass, E-glass, or Kevlar. Unnotched tensile coupons and center-cracked fracture coupons were tested. Elastic properties, complete stress/strain curves, and critical stress intensity values are given. The measured elastic properties compare well with those calculated by classical lamination theory for laminates with linear stress/strain behavior. The glass hybrids had more delamination and higher fracture toughness than the all-graphite or the Kevlar hybrid.

Goree, J. G.↗

NASA NTRS1977

Stress analysis and stress-intensity factors for finite geometry solids containing rectangular surface cracks

The line method of analysis is applied to the Navier-Cauchy equations of elastic equilibrium to calculate the displacement field in a finite geometry bar containing a variable depth rectangular surface crack under extensionally applied uniform loading. The application of this method to these equations leads to coupled sets of simultaneous ordinary differential equations whose solutions are obtained along sets of lines in a discretized region. Using the obtained displacement field, normal stresses, and the stress-intensity factor variation along the crack periphery are calculated for different crack depth to bar thickness ratios. Crack opening displacements and stress-intensity factors are also obtained for a through-thickness, center-cracked bar with variable thickness. The reported results show a considerable potential for using this method in calculating stress-intensity factors for commonly encountered surface crack geometries in finite solids

Gyekenyesi, J. P.↗

NASA NTRS1977

An orthotropic laminate composite containing a layer with a crack

A laminate composite containing an orthotropic layer with a crack situated normal to the interfaces, and bonded to two orthotropic half-planes of dissimilar materials, is considered. The solutions for two different classes of orthotropic materials are presented separately. In each case, the problem is first reduced to a system of dual integral equations, then to a singular integral equation which is subsequently solved numerically for the stress intensity factors at the tip of the crack. The effect of the material properties on the stress intensity factor is investigated. Two cases, the generalized plane stress and the plane strain, are treated simultaneously.

Arin, K.↗

NASA NTRS1978

12-cm magneto-electrostatic containment argon/xenon ion source development

The original 12 cm hexagonal magneto-electrostatic containment (MESC) discharge chamber described by Moore in 1969 has been optimized for argon and xenon operation. Argon mass utilization efficiencies of 65 to 77 percent were achieved at keeper-plus-main discharge energy consumptions of 244 to 422 eV/ion respectively. Xenon performance of 85 to 96 percent mass utilization were realized at 203 to 350 eV/ion. The paper discusses the optimization process and test results.

Ramsey, W. D.↗

NASA NTRS1977

Crystalline polyimides containing 4,4'-bis/3,4-dicarboxyphenoxy/diphenyl sulfide dianhydride

A high degree of crystallinity has been found in unoriented polymer films formed from 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride (BDSDA) and p-phenylenediamine (PDA). Partial crystallinity for a polymer containing BDSDA and benzidine is also reported. A study of the thermal properties of the crystalline polyimides shows crystalline melting points of 426 C and 483 C respectively for the BDSDA-PDA and the BDSDA-benzidine polymers.

Saint Clair, T. L.↗